Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full burden. It discloses that the tool only creates a URL and that a charge can occur only after user confirmation on Stripe. This prevents misinterpretation that the tool itself charges. It also warns against handling card details. Slightly more detail on URL expiry or idempotency would improve transparency.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two sentences, front-loading the core purpose and then adding behavioral and usage context. Every sentence serves a distinct purpose with no wasted words.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given no output schema and no annotations, the description provides enough context for an agent to select and invoke the tool. It covers the primary behavior and safety. Minor omission: it doesn't mention that the URL is likely returned as output, but that is typical for such tools.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, and the schema already provides detailed descriptions for both parameters (pack with pricing, batch_id with resumption behavior). The tool description adds no extra information beyond what's in the schema, so it meets the baseline of 3.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the verb 'Create a hosted Stripe Checkout URL for a prepaid credit pack.' It specifies the resource (prepaid credit pack) and the action (create URL). This distinguishes it from sibling tools like create_screenshot_batch (different resource) and get_account_balance (read-only).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides explicit usage guidance: 'Ask the user before calling it and never handle card details.' This clearly indicates when to use the tool (with user consent) and gives a safety rule. While it doesn't contrast with alternatives, the unique purpose and safety instructions make it clear.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.